A guy walks into a Pharmacy and says to the pharmacist,
"Listen, I have three girls coming over tonight. I've never had three girls at once. I need something to keep me horny, keep me potent."
The pharmacist reaches under the counter, unlocks the bottom drawer and takes out a small cardboard box marked with a label 'Viagra - Extra Strength' and says,
"Here, if you eat this, you'll go nuts for twelve hours."
The guy says "Give me three boxes."
The next day he walks into the same pharmacy, limps up to the pharmacist and pulls down his pants. The pharmacist is shocked to see his penis is black and blue, and skin is hanging off in some places.
In a pained voice, the man moans out,
"Give me some Deep Heat!"
The pharmacist replies in horror,
"You can't put Deep Heat on that!"
The man replies,
"No it's for my arms, the girls didn't show up."